Determining Maximal Intensity
To monitor and modify training variables, it is essential to determine the maximal intensity achievable by the individual client. From this point, the trainer can accurately design exercise programs which will achieve desired physiological adaptations.
- VO2max
Determining the maximal volume of oxygen consumed per kilogram body weight per minute during physical activity is the most accurate method of determining the intensity levels required for exercise prescription. This method is rarely used, as it required the use of sophisticated and expensive testing equipment. This equipment is usually too costly for fitness professionals to purchase, and requires the client to perform at maximal intensity levels, which can be impractical and risky for inactive clients.
- Peak Maximal Heart Rate
This method is commonly used, but is not at all specific all accurate. It involves the following calculation:
Max HR = 220 – age
This calculation relies on the actual maximal heart rate of the individual to be dependent on their age, which is rarely going to occur. It is therefore an estimation of maximal intensity.
- Karvonen Method
This method determines the heart rate reserve to calculate training intensity. The calculation utilises resting heart rate, as heart rate and oxygen uptake is linked during physical activity. The calculation is as follows:
Target Heart Rate = [(Maximal Heart Rate – Resting Heart rate) x desired exercise intensity] + Resting Heart Rate
An example would be a 27-year-old male with a resting heart rate of 65bpm and a desired training intensity of 70% of HRM.
Maximum Heart Rate = 220 – age
= 193
THR = [(193 – 65) x 70%] +65
= [128 x 70%] + 65
= 89,6 + 65
= 155 bpm
- Rate of Perceived Exertion
The is the most subjective method of calculating intensity, as it requires the client to provide their perception of the intensity, or the relative difficulty of the physical exertion. To make this method more accurate, it is advised that the trainer provide the client with the following guidelines:
- The sensation of the increase in heart rate
- The difficulty or ease of breathing during the activity
- The perception of muscle fatigue during the activity.
- The ability of the client to talk during the activity
As the client learns to accurately interpret the sensations they are experiencing, the RPE method will begin to become a valuable technique to prescribe and modify exercise intensity.
Cardiorespiratory Training Goals
To achieve the best results regarding cardiorespiratory training adaptations, it is advised that the following program design guidelines are utilised. These guidelines do not consider individual training goals as well as differing conditioning levels or the rate of adaptation on the client. It is therefore advised that these guidelines are used purely as a guide and not a strict framework for program design.
| Training Goal | Intensity | Duration (Time) | Mode (Type) | Frequency |
| Improve or Maintain General Health | 40 – 65%4 – 6 RPE | 20 – 30 mins | Continuous activity | Min 3 sessions |
| Improve General Conditioning and or Endurance | 60 – 75%6 – 7 RPE | 20 – 40 mins | Continuous activity | Min 4 sessions |
| Improve Conditioning Specific to Activity | 65 – 85%6 – 8 RPE | Activity Dependent | Activity Dependent | 3 – 5 sessions |
| Highest Intensity (Threshold Training) | 75 – 95%7 – 9 RPE | 20 – 30 mins | Intermittent with short rest intervals | 2 – 3 sessions |